As we can see in the zoomed pic, at the [mm] level we have a good polished aluminium surface,
but at the maximum zoom which is 1000x [0.180mm, or 180 microns] times zoomed we can still see the pumps on the surface as the red circle on the last right pic shows.
This roughness will cause some in improper connection between the plate and the dielectric, but at this level it is more than enough for this experiment as the reference capacitor itself got more pumps and scratches on its surface as shown on the following fig 2.x:
As it shown in the first pic where the zoom in 10×10 we can see cracks all over the place, but I have taken just what is in said the red rectangle. We see smooth surface and that to the fact that the plate got a soft metal coted/pouder surface structure.
In the second pic we see the surface with a big crack which is from the
manufacturer, the rest of the vertical cracks are made by me, because of the
hard press on it by the microscope glass.